Why quick clearance can hide the cause
Creating a small passage restores immediate flow but may leave material on the pipe wall or a structural catch point. The drain works until the remaining defect collects enough debris again.
Ask what was found previously, how long the fix lasted and whether the same fixtures failed. That history narrows the options.
- Incomplete removal of deposits
- Root entry through a joint or crack
- Pipe displacement or deformation
- Poor fall and standing deposits
- Repeated unsuitable material
- Downstream shared restriction
